This thesis focuses on the fundamental behavior of CLT floor-to-wall connections during a fire.
Cross-laminated timber (CLT) panelized structures rely on floor-to-wall connections for the load path and stability of the structure. Additionally, the fire performance of these connections is critical to prevent horizontal or vertical fire spread within these...
Conflicts and disasters displace millions of populations worldwide. There is a need for rapid and affordable housing to cater to the needs of the displaced and unhoused population. Experience from previous post-disaster responses shows that temporary housing should be rapidly deployable, planned for months to years, and should be environmentally...
With growing interest in mass timber, especially mass timber panels (MTP), there has been a need to better understand their structural properties. One of the most versatile uses for MTP are as floor systems. Under new code provisions, these floors can be utilized in new and taller building types, but...
Post-tensioned (PT) self-centering shear walls were designed to reduce structural damage from seismic activity. However, these lateral force resistant systems experience post-tension loss negatively affecting the re-centering capability due to delayed deformations experienced by engineered wood products over time. The long-term mechanical response of mass-timber panels to in-plane PT loads...
Timber-concrete composite (TCC) solutions originated in the early twentieth century. There has been a renewed interest in TCC solutions in modern mass timber buildings, especially for floor systems. However due to lack of data, design standards, and code acceptance, TCC solutions require that new mass timber solutions be tested, and...
Civil engineers are aware of the impacts of structures on the global environment but the environmental impacts of a fire within these structures remains unknown. Fires present a unique hazard as it is difficult to predict the probability of the occurrence and the intensity. Traditional methods to identify the environmental...
Cross-laminated timber (CLT) is revolutionizing the use of wood in the construction sector of North America as a solution for walls and diaphragms in mid-rise or even high-rise timber structures on account of its environmental advantages, high strength-to-weight ratio, fire-safety performance, and propensity for prefabrication. However, considering the hygroscopic nature...
Timber-concrete composite (TCC) floors have improved strength and stiffness when compared to timber-only floors, allowing for longer spans in buildings and improved life safety. However, North America does not have codes and standards that recognize TCC floors, particularly the improved life safety performance of these floors in fire. Therefore, alternate...
Mass timber is emerging as a viable form of construction around the world in new markets for wood buildings. The entrance into these markets has driven the demand for more knowledge to enable designs alongside other structural materials such as steel and reinforced concrete.
Large, in-plane tests on cross-laminated timber...
As mass-timber building construction rises around the globe, there exists the need to verify the long-term, in-situ behavior and performance of these structural systems. Structural health monitoring (SHM), generally defined as a damage detection strategy consisting of a network of sensors, a data acquisition system, and algorithms for data analysis,...
The objective of this study was to investigate load paths in an existing light-frame wood structure with complex geometry, using previously established computer modeling methods. The structural model is derived from an existing, multi-level residence located in Corvallis, Oregon. For the purpose of this study, the existing structure was simplified...
Cross-laminated timber (CLT) panels have been gaining popularity as diaphragm elements in mid- to high-rise construction projects. In addition, CLT-concrete composite (CCC) diaphragms have been implemented to expand the use of CLT diaphragms. To understand the behavior of CLT and CCC diaphragms, this research effort sought to characterize the cyclic,...
Cross-Laminated Timber (CLT) is one of the latest engineered wood products to show promising structural features for a variety of structural purposes including resisting lateral loads. For CLT to be widely adopted, its modal behavior needs to be fully evaluated through experimental and numerical methods. It is important to the...
Wood plays a key role in modern electrical infrastructure; crossarms and power poles utilize the high strength to weight ratio, availability and low cost of wood to facilitate the access of power to millions of Americans. However, wood presents a variety of challenges as a material. In structural applications, one...
Connections in mass timber structural systems dissipate energy and transfer lateral forces from mass timber elements such as shear walls and diaphragms, providing critical load paths. Cross-laminated timber (CLT) is a prominent mass timber material used to manufacture wall and floor assemblies. Fire performance research of CLT walls and floors...
Timber engineering is currently in the midst of a significant evolution due to the rise of mass timber products, like cross-laminated timber (CLT). Increasing numbers of structural engineers are facing the challenge of designing lateral-force-resisting systems (LFRS) for multistory CLT structures. LFRS solutions such as steel frames, concrete cores, or...
Cross-Laminated Timber (CLT) is a prefabricated building material that is relatively new to the United States and North America. It consists of no less than three layers of graded, dimensional lumber glued in alternating longitudinal and transverse layers to create a panel that can be used for various building applications...
There are over 130 million wood poles supporting electrical transmission and distribution lines in the U.S. The vast majority of these poles are preservative treated to prolong their useful life. In some cases, however, the depth of treatment is relatively shallow, leaving a deep zone of moderately durable, untreated heartwood....
One of the recent additions to the panoply of engineered wood products is cross-laminated timber (CLT). CLT is a prefabricated, large-scale, solid wood panel that consists of multiple layers of lumbers stacked together, with each layer arranged perpendicular to the next layer, glued with structural grade adhesives, and pressed. The...
Many publications, documents, codes and guidelines exist related to the seismic evaluation and rehabilitation design of existing buildings. This report discusses the assumptions and methods employed for investigation of two wood structures using four references: FEMA 154, FEMA 356, ASCEI per SEI 31, and 1997 UBC. The screening performed using...
The goal of this project is to contribute to the development of design values for cross-laminated timber (CLT) diaphragms in the seismic load-resisting system for buildings. Monotonic and cyclic tests to determine strength and stiffness characteristics of 2.44 m (8 ft) long shear connections with common self-tapping screws were performed....
In the residential sector, wood is the predominant construction material. In the commercial sector and in mid‐rise construction, the use of wood is limited because of a multitude of reasons, including building code restrictions, the perception of wood as a structural material, fire code requirements, and lack of knowledge and...
The objectives of this study are to use SAP2000 to investigate lateral load paths and system behavior in a modular, light-frame wood structure by investigating different foundation configurations and to further develop and validate existing modeling techniques of shear wall elements based on the Perforated Shear Wall Method. The modeling...
Many nondestructive techniques for structural health monitoring are subjective and based on visual observations of degradation. In addition, dynamic properties of structures are already used to obtain quantitative structural health data. However, most current data collection is limited to localized damage on the structure, rather than global response. Recent research...
Engineered wood composites are used in many structural applications and are intended for dry use. However, these materials may encounter significant amounts of wetting while in service, which can lead to structural failures. This study combined aspects of wood science, mechanics, structural engineering, and mycology to assess changes in material...
The development of cross-laminated timber (CLT) panel technology has opened up new opportunities for wood in tall buildings. Several characteristics including seismic performance and speed of construction have raised interest among designers. As CLT gains acceptance in the industry, alternative structural solutions need to be investigated to improve performance of...
There are about 80 million single-family dwellings (SFD) in the United States, predominantly of wood-frame construction. Of these, 68% are owner occupied. A home is typically the largest single investment of a family, and is often not covered by earthquake insurance, even where it is available. Of all SFD in...
The objective of this study was to compare light wood framing and traditional timber
framing quantitatively through environmental impact assessment and load path analysis. This
research was inspired by a traditional timber frame structure constructed in Vermont in 2011, and
the design of structures considered within reflect the general characteristics...
As oriented strand board (OSB) increases in use as an engineered wood product, improving the in-plane shear properties will allow more efficient use of the material as well as open up other opportunities for OSB to be used in engineered wood products with high shear stresses. Based on classical laminated...
The objective of this study was to develop and validate practical modeling
methods for investigating load paths and system behavior in a realistic, light-frame wood
structure. The modeling methods were validated against full-scale tests on subassemblies
and an L-shaped house. The model of the L-shaped house was then modified
and...
The objective of this project was to evaluate methods to remediate a wood I-joist with a single, circular hole in the web while leaving utilities in place. The methods were experimentally evaluated with a full-scale bending test using four equally spaced point loads. There were three depths of joists with...
During the past several decades, earthquakes have caused extensive damage to
buildings, including wood-frame, single-family dwellings, in the United States. In
order to mitigate future losses, existing buildings in earthquake prone areas should be
evaluated for their seismic safety. This is also an important issue for buildings in
Oregon due...
Since 2004 there have been multiple devastating tsunamis around the globe triggered by large magnitude earthquakes; with the most recent being the Tohoku, Japan tsunami in March 2011. These tsunamis have caused significant loss of life and damage to the coastal communities impacted by these powerful waves. The resulting devastation...
The goal of this study was to optimize a through-boring pattern that will provide adequate preservative penetration while minimizing the reduction in overall pole bending strength. Hole spacing was developed using longitudinal and transverse chemical penetration data from previous studies. Finite element analysis was used as a preliminary assessment tool...
Key parts of the lateral force resisting system in wood-frame buildings
are the shearwafls and the connections. The connections in wooden buildings
are the primary source of ductility and energy dissipation; these are essential
properties when buildings are exposed to lateral forces, such as wind and
earthquakes. Shearwall design is...
The objectives of this study were to evaluate the performance of wood frame shear walls
under monotonic, cyclic and earthquake loads by: (1) estimating the variability of shear wall
performance, (2) comparing the performance of walls under each loading protocol, (3) evaluating
the effects of anchorage on wall performance, and...
The overall goal of this study is to evaluate the earthquake performance of wood frame
shear walls, and more specifically: (1) to compare the performance differences of fully and
partially anchored walls under monotonic, cyclic, and earthquake loads, (2) to compare wall
performance under earthquake loads with that of standardized...
Friction dampers have been used successfully to dissipate seismic
energy in steel and concrete structures. The application is new to timber
structures. The objectives of this research were to design a slotted bolted
connection (SBC) and evaluate its potential as a passive energy damper in
timber brace.
The research was...
The objectives of this study are: (1) to evaluate the effect of reference
displacement on wall behavior under fully reversed cyclic loading using the
CUREE test protocol and (2) to assess damage accumulation (visible fastener
damage and stiffness degradation) for the imposed drift levels. All tests were
conducted on identical...
The objective of this study was to determine the effect of misplaced hold-downs
on the static and cyclic behavior of wood shear walls. Three shear wall
configurations were considered in this study. The first configuration (control) had
hold-downs at the ends of the wall (wall type 1), the second configuration...
Engineers, in practice, are often faced with the challenge of evaluating a fire-damaged structure and developing a rehabilitation and retrofit plan. In order to decide on a rehabilitation and retrofit plan, information on thermal degradation of building materials and connections are vital. A critical knowledge gap exists in terms of...
Engineering analysis of heavy timber structures under dynamic loads
is generally lacking. Some literature suggests that heavy timber structures
are stiffer than expected, but popular engineering opinion is to the contrary.
In addition, prior research has shown that passive friction dampers can be
used in timber structures for the intended...
The overall goal of this project was to design a wood frame shear wall that could withstand greater displacement before damage occurred to the Gypsum Wall Board (GWB). More specifically, the objectives of the study were: (1) to evaluate damage to the GWB in alternative shear wall designs at 1%,...
The objective of this project was to develop an analytical model of a light-framed wood structure using a prevalent structural analysis computer program in order to evaluate system effects and define load paths within the structure, especially under extreme wind events. Simplified modeling techniques and material definitions were developed and...
In recent years, log structures have been marketed as an alternative
to conventional light-frame wood structures. Log structures are constructed
using round timbers (or manufactured timbers) that are stacked vertically
and have interlocking corners. Thru-rods and lag screws are used to
provide inter-log connections. This project was conducted to evaluate...
The goal of this study was to develop an understanding of the nature of surge wave loading on
wood framed residential structures for a variety of building configurations and test conditions.
The objectives of the study were: (1) to measure forces on a 1/6th scale wood framed
residential structure, (2)...
The overall goal of this study was to evaluate an alternative to
traditional wood framed shear wall construction. This study introduced the
innovative idea of using a water and seismic damage resistant, wood-concrete-
composite (WCC) construction instead of an all-wood design. The
WCC design consisted of a thin shell of...
The overall goal of this study was to gain an insight into the load sharing aspect between oriented strand board (OSB) and gypsum wall board (GWB) in shear wall assembly during racking load. More specifically the objectives of the study were to: (1) evaluate qualitatively the load sharing between OSB...
Light-frame construction practices and materials have changed greatly
over the past 100 years. Contemporary research has focused on modern construction; thus, we know a great deal about the behavior of modern lightframe buildings under lateral forces. However, there are many light-frame buildings that were built prior to the introduction of...
Heavy timber framing relies primarily on bracing to withstand lateral loads due to earthquakes and wind events. Bracing configurations in heavy timber framed buildings vary widely and include cross bracing, knee bracing, and other geometries. Many heavy timber frames constructed during colonial American times are still standing, exceeding the expected...
